FIG. 10 shows a conventional panel and its driving apparatus. On panel 1, a sustaining discharge generated between pairs of scan electrodes and sustain electrodes causes a phosphor to emit light for display. 2M rows of pairs of scan electrodes SCNj and sustain electrodes SUSj(j=1 to 2M) and N rows of data electrodes Di (i=1 to N), which are arranged orthogonally to the scan electrodes and sustain electrodes, constitute a matrix with 2M rows and N columns. Discharge cells are formed at intersections between the data electrode Di and the pairs of scan electrodes SCNj and sustain electrodes SUSj. Over panel 1, pairs of scan electrodes SCNj and sustain electrodes SUSj extend out reversely to each other. The scan electrodes in any adjacent rows extend out reversely to each other over the panel. The sustain electrodes in any adjacent rows extend out reversely to each other over the panel.
In other words, scan electrodes SCN1, SCN3, . . . SCN2m−1 in odd-numbered rows extend out to the left side of panel 1 and are connected to a scan electrode driving circuit 2a which drives these scan electrodes. Sustain electrodes SUS1, SUS3, . . . SUS2M−1 in odd-numbered rows extend out to the right side of panel 1 and are connected to a sustain electrode driving circuit 3a which drives these sustain electrodes. Scan electrodes SCN2, SCN4, . . . SCN2M in even-numbered rows extend out to the right side of panel 1 and are connected to scan electrode driving circuit 2b which drives these scan electrodes. Sustain electrodes SUS2, SUS4, . . . SUS2M in even-numbered rows extend out to the left side of panel 1 and are connected to sustain electrode driving circuit 3b which drives these sustain electrodes. Data electrodes D1, . . . DN extend out to the upside of panel 1 and are connected to a data electrode driving circuit 4 for driving the data electrodes.
When a sustain pulse voltage for causing the sustaining discharge is applied on the sustain electrodes or scan electrodes on panel 1, pulse currents having extremely short time-width that do not contribute to light emission run through respective rows, and therefore electromagnetic waves occur in the respective rows. Because the currents in any of the adjacent rows run reversely to each other, the electromagnetic waves have reverse polarities and therefore cancel each other.
However, when an operation of scan electrode driving circuit 2a is out of accord with that of scan electrode driving circuit 2b, an operation of sustain electrode driving circuit 3a is thereby out of accord with sustain electrode driving circuit 3b. And if the applying time of the sustain pulse voltages in any of the adjacent rows is even slightly out of accord with each other, then the time of generating pulse currents is out of accord with each other, and therefore the electromagnetic waves do not cancel each other. As a result, the electromagnetic waves are radiated out of the panel, which therefore causes the other electronic apparatus to malfunction.
For preventing the electromagnetic wave from being radiated out of the panel, it is considered that all scan electrodes SCN1–SCN2m and sustain electrodes SUS1–SUS2M extend out in the same direction, such as on the left side of the panel, for example, and are connected to the scan electrode driving circuit and the sustain electrode driving circuit, respectively. In this case, currents which are the same in amplitude run reversely through the scan electrode and the sustain electrode in each row, and thus the electromagnetic waves generated by reversely running currents therefore cancel each other. As a result, the electromagnetic waves are not radiated out of the panel.
In this case, however, the sum of the path length through which the current runs from the scan electrode driving circuit to a discharge cell and the path length through which the current runs from the discharge cell to the sustain electrode driving circuit varies depending on a position of the discharge cell in the panel. In other words, the current running path length to the discharge cell on the right side of the panel is smaller than that on the left side of the panel. Therefore, due to a voltage drop caused by the resistance of the electrodes, a voltage that is applied between the scan electrode and the sustain electrode for each discharge cell varies depending on the position of the discharge cells. Since strength of the discharge varies for each cell, brightness irregularity occurs.